﻿using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Configuration;
using System.Data;
using System.Data.SQLite;
using System.Collections;
using System.Text;

namespace CqusInfo.CR.SqlHelper
{
    /**************************************
    * 作用：SQLLite Server操作实现
    * 作者：XXX
    * 日期: 2011-03-08
    * 网址：www.redglove.net
    **************************************/
    public class SQLiteHelper
    {
        //数据库连接字符串(web.config来配置)，可以动态更改SQLString支持多数据库.        
       
        
        private static readonly string appBasePath = AppDomain.CurrentDomain.BaseDirectory.ToString();

        public static readonly string connectionString = @"Data Source=" + appBasePath + ConfigurationManager.ConnectionStrings["connectionStr"].ToString();

        public SQLiteHelper() { }

        #region 公用方法

        /// <summary>
        /// 得到最大ID
        /// </summary>
        /// <param name="FieldName">字段名</param>
        /// <param name="TableName">表名</param>
        /// <returns>返回得到的最大数据</returns>
        public static Int32 GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = ExecuteScalar(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return Int32.Parse(obj.ToString());
            }
        }

        /// <summary>
        /// 得到所有数据
        /// </summary>
        /// <param name="TableName">表名</param>
        /// <param name="isDel">true:已删除 false：未删除</param>
        /// <returns>返回得到的最大数据</returns>
        public static Int32 GetCounts(string TableName,bool isDel)
        {
            string strsql = "select count(*) from " + TableName + " where c_d_isDel=" + isDel;
            object obj = ExecuteScalar(strsql);
            if (obj == null)
            {
                return 0;
            }
            else
            {
                return Int32.Parse(obj.ToString());
            }
        }

        /// <summary>
        /// 判断用户是否存在
        /// </summary>
        /// <param name="strSql">Sql语句</param>
        /// <returns>true：存在 false：不存在</returns>
        public static bool Exists(string strSql)
        {
            object obj = ExecuteScalar(strSql);
            Int32 cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = Int32.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        /// <summary>
        /// 带参数判断用户是否存在
        /// </summary>
        /// <param name="strSql">Sql语句</param>
        /// <param name="cmdParms">参数</param>
        /// <returns>true：存在 false：不存在</returns>
        public static bool Exists(string strSql, params SQLiteParameter[] cmdParms)
        {
            object obj = ExecuteScalar(strSql, cmdParms);
            Int32 cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = Int32.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }

        #region Query (考虑where语句后少于或等于一个and的情况，大于一个and，则自己写Sql语句实现，若那样重载还不如自己写Sql语句)
        /// <summary>
        /// 查询所有信息
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="page">第几页，需要减一</param>
        /// <param name="takeItem">每页显示的数目</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string tableName, Int32 page, Int32 takeItem)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("select * from " + tableName + " limit " + (page - 1) * takeItem + "," + takeItem);

            return ExecuteQuery(sqlStr.ToString());
        }
        /// <summary>
        /// 查询所有删除或者未删除的信息
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="delFieldName">字段名（依据这个字段查找，如：c_b_isdel）</param>
        /// <param name="isDel">true：已删除 false：未删除</param>
        /// <param name="page">第几页，需要减一</param>
        /// <param name="takeItem">每页显示的数目</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string tableName, string delFieldName, bool isDel, Int32 page, Int32 takeItem)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("select * from " + tableName + " limit " + (page - 1) * takeItem + "," + takeItem + " where " + delFieldName + "=@isDel");

            SQLiteParameter[] parameters ={
                                         new SQLiteParameter("@isDel",DbType.Boolean)
                                         };
            parameters[0].Value = isDel;
            return ExecuteQuery(sqlStr.ToString(), parameters);
        }
        /// <summary>
        /// 查询信息依据字段，不考虑是否删除
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="idFieldName">字段名（依据这个字段查找，如：c_vc_userName）</param>
        /// <param name="id">字段值</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string tableName, string idFieldName, string id)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("select * from " + tableName + " where " + idFieldName + "=@id");

            SQLiteParameter[] parameters ={
                                         new SQLiteParameter("@id",DbType.String)
                                         };
            parameters[0].Value = id;
            return ExecuteQuery(sqlStr.ToString(), parameters);
        }
        /// <summary>
        /// 查询具体的某一条信息，删除的或者未删除的
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="FieldName">字段名（依据这个字段查找，如：c_vc_userName）</param>
        /// <param name="id">字段值</param>
        /// <param name="delFieldName">判断删除的字段（c_b_isDel）</param>
        /// <param name="isDel">true：已删除 false：未删除</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string tableName, string idFieldName, string id, string delFieldName, bool isDel)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("select * from " + tableName + " where " + delFieldName + "=@isDel and " + idFieldName + "=@id");

            SQLiteParameter[] parameters ={
                                         new SQLiteParameter("@isDel",DbType.Boolean),
                                         new SQLiteParameter("@id",DbType.String)
                                         };
            parameters[0].Value = isDel;
            parameters[1].Value = id;
            return ExecuteQuery(sqlStr.ToString(), parameters);
        }
        /// <summary>
        /// 查询信息,使用where语句后的两个条件
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="FieldName">字段名（依据这个字段查找，如：c_vc_userName）</param>
        /// <param name="FieldNameValue">true：条件一 false：条件二</param>
        /// <param name="delFieldName">判断删除的字段（c_b_isDel）</param>
        /// <param name="isDel">true：已删除 false：未删除</param>
        /// <param name="page">第几页，需要减一</param>
        /// <param name="takeItem">每页显示的数目</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string tableName, string FieldName, bool FieldNameValue, string delFieldName, bool isDel,Int32 page, Int32 takeItem)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("select * from " + tableName + " limit " + (page - 1) * takeItem + "," + takeItem + " where " + delFieldName + "=@isDel and " + FieldName + "=@FieldNameValue");

            SQLiteParameter[] parameters ={
                                         new SQLiteParameter("@isDel",DbType.Boolean),
                                         new SQLiteParameter("@FieldNameValue",DbType.Boolean)
                                         };
            parameters[0].Value = isDel;
            parameters[1].Value = FieldNameValue;
            return ExecuteQuery(sqlStr.ToString(), parameters);
        }
        #endregion

        #region Delete
        /// <summary>
        /// 执行彻底删除
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="idFieldName">id字段名（c_vc_userName）</param>
        /// <param name="id">id值</param>
        /// <returns>1：成功 0：失败</returns>
        public static Int32 Delete(string tableName, string idFieldName, string id)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("delete from " + tableName + " where " + idFieldName + "=@id");

            SQLiteParameter[] parameters ={
                                         new SQLiteParameter("@id",DbType.String)
                                         };
            parameters[0].Value = id;

            return SqlHelper.SQLiteHelper.ExecuteNonQuery(sqlStr.ToString(), parameters);
        }
        /// <summary>
        /// 执行伪删除
        /// </summary>
        /// <param name="tableName">表名（tb_User）</param>
        /// <param name="idFieldName">id字段名（c_vc_userName）</param>
        /// <param name="id">id值</param>
        /// <param name="delFieldName">删除字段名（c_b_isDel）</param>
        /// <param name="isDel">true：已删除 false：未删除</param>
        /// <returns>1：成功 0：失败</returns>
        public static Int32 Delete(string tableName,string idFieldName, string id,string delFieldName, bool isDel)
        {
            StringBuilder sqlStr = new StringBuilder();
            sqlStr.Append("update " + tableName + " set " + delFieldName + "=@isDel where " + idFieldName + "=@id");

            SQLiteParameter[] parameters ={
                                         new SQLiteParameter("@isDel",DbType.Boolean),
                                         new SQLiteParameter("@id",DbType.String)
                                         };
            parameters[0].Value = isDel;
            parameters[1].Value = id;

            return SqlHelper.SQLiteHelper.ExecuteNonQuery(sqlStr.ToString(), parameters);
        }
        #endregion

        #endregion

        #region  执行简单SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static Int32 ExecuteNonQuery(string SQLString)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        Int32 rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SQLite.SQLiteException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行SQL语句，设置命令的执行等待时间
        /// </summary>
        /// <param name="SQLString"></param>
        /// <param name="Times"></param>
        /// <returns></returns>
        public static Int32 ExecuteNonQueryByTime(string SQLString, Int32 Times)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        cmd.CommandTimeout = Times;
                        Int32 rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (System.Data.SQLite.SQLiteException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>        
        public static void ExecuteTran(ArrayList SQLStringList)
        {
            using (SQLiteConnection conn = new SQLiteConnection(connectionString))
            {
                conn.Open();
                SQLiteCommand cmd = new SQLiteCommand();
                cmd.Connection = conn;
                SQLiteTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for (Int32 n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n].ToString();
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
            }
        }

        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static Int32 ExecutePrco(string SQLString, string content)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
                SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    Int32 rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static object ExecutePrcoGet(string SQLString, string content)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
                SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    object obj = cmd.ExecuteScalar();
                    if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                    {
                        return null;
                    }
                    else
                    {
                        return obj;
                    }
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static Int32 ExecuteInsertImg(string strSQL, byte[] fs)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
                SQLiteParameter myParameter = new SQLiteParameter("@fs", DbType.Binary);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    Int32 rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SQLite.SQLiteException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object ExecuteScalar(string SQLString)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SQLite.SQLiteException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，返回SQLiteDataReader(使用该方法切记要手工关闭SQLiteDataReader和连接)
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SQLiteDataReader</returns>
        public static SQLiteDataReader ExecuteReader(string strSQL)
        {
            SQLiteConnection connection = new SQLiteConnection(connectionString);
            SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
            try
            {
                connection.Open();
                SQLiteDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SQLite.SQLiteException e)
            {
                throw new Exception(e.Message);
            }
            //finally //不能在此关闭，否则，返回的对象将无法使用
            //{
            //    cmd.Dispose();
            //    connection.Close();
            //}    
        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet ExecuteQuery(string SQLString)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SQLite.SQLiteException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        /// <summary>
        /// 查询数据带表名
        /// </summary>
        /// <param name="SQLString">Sql语句</param>
        /// <param name="TableName">表名</param>
        /// <returns>DataSet</returns>
        public static DataSet ExecuteQuery(string SQLString, string TableName)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
                    command.Fill(ds, TableName);
                }
                catch (System.Data.SQLite.SQLiteException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        /// <summary>
        /// 执行查询语句，返回DataSet,设置命令的执行等待时间
        /// </summary>
        /// <param name="SQLString">Sql语句</param>
        /// <param name="Times">执行等待时间</param>
        /// <returns>dataset</returns>
        public static DataSet ExecuteQuery(string SQLString, Int32 Times)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
                    command.SelectCommand.CommandTimeout = Times;
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SQLite.SQLiteException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        #endregion

        #region 执行带参数的SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static Int32 ExecuteNonQuery(string SQLString, params SQLiteParameter[] cmdParms)
        {
            //if (String.IsNullOrEmpty(connectionString))
            //{
            //    connectionString = GetDefaultconnectionString();
            //}
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        Int32 rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (System.Data.SQLite.SQLiteException E)
                    {
                        CqusInfo.CR.Tool.MyLogger.Error(E.Message + "数据添加、修改、删除发生异常！");
                        return 0;
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SQLiteParameter[]）</param>
        public static void ExecuteTran(Hashtable SQLStringList)
        {
            using (SQLiteConnection conn = new SQLiteConnection(connectionString))
            {
                conn.Open();
                using (SQLiteTransaction trans = conn.BeginTransaction())
                {
                    SQLiteCommand cmd = new SQLiteCommand();
                    try
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            SQLiteParameter[] cmdParms = (SQLiteParameter[])myDE.Value;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            Int32 val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();

                            trans.Commit();
                        }
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object ExecuteScalar(string SQLString, params SQLiteParameter[] cmdParms)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                using (SQLiteCommand cmd = new SQLiteCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SQLite.SQLiteException e)
                    {
                        CqusInfo.CR.Tool.MyLogger.Error(e.Message + "数据查询发生异常！");
                        return null;
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，返回SQLiteDataReader (使用该方法切记要手工关闭SQLiteDataReader和连接)
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SQLiteDataReader</returns>
        public static SQLiteDataReader ExecuteReader(string SQLString, params SQLiteParameter[] cmdParms)
        {
            SQLiteConnection connection = new SQLiteConnection(connectionString);
            SQLiteCommand cmd = new SQLiteCommand();
            try
            {
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                SQLiteDataReader myReader = cmd.ExecuteReader();
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (System.Data.SQLite.SQLiteException e)
            {
                throw new Exception(e.Message);
            }
            //finally //不能在此关闭，否则，返回的对象将无法使用
            //{
            //    cmd.Dispose();
            //    connection.Close();
            //}    

        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet ExecuteQuery(string SQLString, params SQLiteParameter[] cmdParms)
        {
            using (SQLiteConnection connection = new SQLiteConnection(connectionString))
            {
                SQLiteCommand cmd = new SQLiteCommand();
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                using (SQLiteDataAdapter da = new SQLiteDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (System.Data.SQLite.SQLiteException ex)
                    {
                        CqusInfo.CR.Tool.MyLogger.Error(ex.Message + "数据查询发生异常！");
                    }
                    return ds;
                }
            }
        }

        /// <summary>
        /// 执行语句操作
        /// </summary>
        /// <param name="cmd">cmd</param>
        /// <param name="conn">连接conn</param>
        /// <param name="trans">事物</param>
        /// <param name="cmdText">语句</param>
        /// <param name="cmdParms">参数</param>
        private static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn, SQLiteTransaction trans, string cmdText, SQLiteParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null)
            {
                foreach (SQLiteParameter parameter in cmdParms)
                {
                    if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
                        (parameter.Value == null))
                    {
                        parameter.Value = DBNull.Value;
                    }
                    cmd.Parameters.Add(parameter);
                }
            }
        }

        /// <summary>
        /// 获取默认的连接字符串，请保证存在~/App_Data/SQLitedb.db3
        /// </summary>
        /// <returns></returns>
        //public static string GetDefaultconnectionString()
        //{
        //    string dbfilepath = AppBasePath + "App_Data\\sql_ReportData.db3";

        //    if (!System.IO.File.Exists(dbfilepath))
        //    {
        //        throw new System.IO.FileNotFoundException("对于路径为：" + dbfilepath + " 的文件未找到");
        //    }
        //    System.Data.SqlClient.SqlConnectionStringBuilder conSb = new SqlConnectionStringBuilder();
        //    conSb.DataSource = dbfilepath;
        //    conSb.Password = "123456";
        //    return conSb.ToString();
        //    //return String.Format("data source=\"{0}\";password=administrator", dbfilepath);
        //}
        ///// <summary>
        ///// 根据SQLite文件所在路径获得连接字符串
        ///// </summary>
        ///// <param name="virDBFilePath">相对系统根目录的路径，必须以~开头</param>
        ///// <param name="pwd">数据库密码，如果不设则为默认密码</param>
        ///// <returns></returns>
        //public static void GetDefaultconnectionString(string virDBFilePath, string pwd)
        //{
        //    if (!virDBFilePath.StartsWith("~/") && !virDBFilePath.StartsWith("~\\"))
        //    {
        //        throw new ArgumentException("请保证virDBFilePath为相对路径，并以~开头");
        //    }
        //    virDBFilePath = AppBasePath + virDBFilePath.Replace("~/", "").Replace("~\\", "");
        //    if (!System.IO.File.Exists(virDBFilePath))
        //    {
        //        throw new System.IO.FileNotFoundException("对于路径为：" + virDBFilePath + " 的文件未找到");
        //    }
        //    System.Data.SqlClient.SqlConnectionStringBuilder conSb = new SqlConnectionStringBuilder();
        //    conSb.DataSource = virDBFilePath;
        //    conSb.Password = String.IsNullOrEmpty(pwd) ? "123456" : pwd;
        //    connectionString = conSb.ToString();
        //    //return String.Format("data source=\"{0}\";password={1}", virDBFilePath, String.IsNullOrEmpty(pwd) ? "administrator" : pwd);
        //}
        #endregion

        #region 参数转换
        /// <summary>
        /// 放回一个SQLiteParameter
        /// </summary>
        /// <param name="name">参数名字</param>
        /// <param name="type">参数类型</param>
        /// <param name="size">参数大小</param>
        /// <param name="value">参数值</param>
        /// <returns>SQLiteParameter的值</returns>
        public static SQLiteParameter MakeSQLiteParameter(string name, DbType type, Int32 size, object value)
        {
            SQLiteParameter parm = new SQLiteParameter(name, type, size);
            parm.Value = value;
            return parm;
        }

        public static SQLiteParameter MakeSQLiteParameter(string name, DbType type, object value)
        {
            SQLiteParameter parm = new SQLiteParameter(name, type);
            parm.Value = value;
            return parm;
        }
        #endregion

        #region 使用方法
        /*
        /// <summary>
        /// 判断用户是否存在
        /// </summary>
        /// <param name="name">用户名称</param>
        /// <returns></returns>
        public bool UserExists(string name)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("select count(*) n from Users");
            strSql.Append(" where UserName=@UserName ");
            SQLiteParameter[] parameters = {
                        SQLiteHelper.MakeSQLiteParameter("@UserName", DbType.String,30,name)};

            return SQLiteHelper.Exists(strSql.ToString(), parameters);
        }
        /// <summary>
        /// 增加一个用户
        /// </summary>
        /// <param name="name">用户名</param>
        /// <param name="pwd">密码</param>
        /// <returns></returns>
        public Int32 CreateUser(string name, string pwd)
        {
            if (!UserExists(name))
            {
                StringBuilder strSql = new StringBuilder();
                strSql.Append("insert into t_UserGroup(");
                strSql.Append("UserName,Password)");
                strSql.Append(" values (");
                strSql.Append("@UserName,@Password)");
                SQLiteParameter[] parameters = {
                        SQLiteHelper.MakeSQLiteParameter("@UserName", DbType.String,30,name),
                        SQLiteHelper.MakeSQLiteParameter("@Password", DbType.String,128,pwd)
                        };
            }
            
            return SQLiteHelper.ExecuteSql(strSql.ToString(), parameters)；
        }

        /// <summary>
        /// 更新一条数据
        /// </summary>
        /// <param name="model">用户分组实体类</param>
        /// <returns></returns>
        public bool UpdateUser(Int32 id, string name, string pwd)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("update Users set ");
            strSql.Append("UserName=@UserName,");
            strSql.Append("Password=@Password");
            strSql.Append(" where UserID=@UserID");
            SQLiteParameter[] parameters = {
                        SQLiteHelper.MakeSQLiteParameter("@UserID", DbType.Int32,11,id),
                        SQLiteHelper.MakeSQLiteParameter("@UserName", DbType.String,30,name),
                        SQLiteHelper.MakeSQLiteParameter("@Password", DbType.String,128,pwd)};

            if (SQLiteHelper.ExecuteSql(strSql.ToString(), parameters) >= 1)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        /// <summary>
        /// 删除用户
        /// </summary>
        /// <param name="ID">用户ID</param>
        /// <returns></returns>
        public Int32 DeleteUser(Int32 id)
        {
            Int32 ret = 0;
            string strSql3 = "delete from Users where UserID=@UserID";
            SQLiteParameter[] parameters = {
                        SQLiteHelper.MakeSQLiteParameter("@UserID", DbType.Int32,4,id)};

            if (SQLiteHelper.ExecuteSql(strSql3, parameters) >= 1)
            {
                ret = 1;
            }
            else
            {
                ret = 0;
            }

            return ret;
        }

        /// <summary>
        /// 获得用户分组数据列表
        /// </summary>
        /// <param name="strWhere">Where条件</param>
        /// <returns></returns>
        public DataSet GetUserList(string strWhere)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("select * FROM Users ");

            if (strWhere.Trim() != "")
            {
                strSql.Append(" where " + strWhere);
            }
            strSql.Append(" order by UserID desc");

            return SQLiteHelper.ExecuteQuery(strSql.ToString());
        }
         * 
         * 
         *注意：1. @@IDENTITY LAST_INSERT_ROWID()
                2. SELECT cn = COUNT(*) FROM ... SELECT COUNT(*) cn FROM ...
                3. LIMIT startIndex,itemCn 这儿的startIndex是从0开始的，而ROW_NUMBER()是从1开始的
                4. sqlite中没有SELECT TOP,用LIMIT即可
                5. SQLite自增字段，如果在事务中插入数据失败，并不会占用增长后的id，而sql server中对应的id将无效
                6. SQLite中没有GETDATE日期函数，在类中加入参数如下DbType.DateTime,DateTime.Now.ToString("s")
                7. SQLite支持REPLACE INTO语法,sql server 2008中支持merge to 
         */
        #endregion
    }
}